Spiraeas are tough shrubs with lots of use in the landscape and can be started from cuttings taken in early summer. You can clip off a section of branch as long as a pencil, strip the lower leaves from the bottom half of the cutting and poke the cut end into potting soil. Keep moist and place in the shade. Roots will form in a few months. You can also bend a branch to the ground, cover the middle of the branch with soil and hold it close to the earth with a stone or bent wire and roots will form where the branch is buried. Then next spring you can cut the branch from the mother plant and enjoy a rooted cutting without having to tend a cutting placed in a pot.  Take lots of cuttings at different times of years as there are many types of spiraeas and none of them will suffer from clipping off sections of branch as you experiment with taking cuttings. Write back and let us know what worked best for you. Keep growing, Marianne Binetti